Role of Cavernous Sinus Extension and MRI T2 Hypointensity in the Extent of Resection following Trans-Sphenoidal Surgery for Giant Pituitary Adenomas.

Abstract

Giant pituitary adenomas (GPA) pose a significant neurosurgical challenge. In this study, we present an experience of 60 consecutive patients with GPA operated by trans-sphenoidal surgery (microscopic/endoscopic). The aim of this study was to elucidate preoperative factors predicting extent of resection (EOR) following transsphenoidal surgery for GPA. The study was a retrospective evaluation of 60 adult patients (>18 years) with GPA operated over a decade. The patients were analyzed for their clinical presentation, EOR, radiology, visual outcome, endocrinological outcome, and complications. The mean age of the cohort was 41.5 ± 13.3 years, mean tumor volume was 38.2 ± 19.1 cm3, and mean follow-up was 30.6 ± 21.7 months. Improvement in vision was seen in forty patients (66.7%), while another 16 (26.7%) had stable vision as prior to surgery. Duration of visual symptoms was found to be statistically significantly associated with postoperative improvement of vision (P = 0.001). Twenty-four patients (40.0%) underwent subtotal resection (STR), while the remaining 36 patients (60.0%) underwent either gross total or near-total resection. Factors associated with STR were retrosellar (P = 0.04), subfrontal (P = 0.02), Knosp 3,4 cavernous sinus extension (P = 0.03), and MRI T2 hypointensity (P = 0.02). During follow-up, eight patients (13.3%) had radiological evidence of growth of residual tumor. Most cases of GPA can be adequately handled by trans-sphenoidal surgery. The presence of retrosellar, subfrontal, cavernous sinus extensions, and T2 hypointensity should alert the surgeon for likelihood of STR, postoperative residual tumor hemorrhage and need for second-stage endonasal or transcranial surgery. However, utilization of extended endoscopic route has allowed good debulking of tumors having subfrontal and parasellar extensions, which was not possible previously using traditional microscopic transsphenoidal surgery.